2016 Update

Task/Factors-of-an-integer/JavaScript/factors-of-an-integer-6.js

@@ -0,0 +1,73 @@
+(function (lstTest) {
+    'use strict';
+
+    // INTEGER FACTORS
+
+    // integerFactors :: Int -> [Int]
+    let integerFactors = (n) => {
+            let rRoot = Math.sqrt(n),
+                intRoot = Math.floor(rRoot),
+
+                lows = range(1, intRoot)
+                .filter(x => (n % x) === 0);
+
+            // for perfect squares, we can drop
+            // the head of the 'highs' list
+            return lows.concat(lows
+                .map(x => n / x)
+                .reverse()
+                .slice((rRoot === intRoot) | 0)
+            );
+        },
+
+        // range :: Int -> Int -> [Int]
+        range = (m, n) => Array.from({
+            length: (n - m) + 1
+        }, (_, i) => m + i);
+
+
+
+
+
+    /*************************** TESTING *****************************/
+
+    // TABULATION OF RESULTS IN SPACED AND ALIGNED COLUMNS
+    let alignedTable = (lstRows, lngPad, fnAligned) => {
+            var lstColWidths = range(
+                    0, lstRows
+                    .reduce(
+                        (a, x) => (x.length > a ? x.length : a),
+                        0
+                    ) - 1
+                )
+                .map((iCol) => lstRows
+                    .reduce((a, lst) => {
+                        let w = lst[iCol] ? lst[iCol].toString()
+                            .length : 0;
+                        return (w > a) ? w : a;
+                    }, 0));
+
+            return lstRows.map((lstRow) =>
+                    lstRow.map((v, i) => fnAligned(
+                        v, lstColWidths[i] + lngPad
+                    ))
+                    .join('')
+                )
+                .join('\n');
+        },
+
+        alignRight = (n, lngWidth) => {
+            let s = n.toString();
+            return Array(lngWidth - s.length + 1)
+                .join(' ') + s;
+        };
+
+    // TEST
+    return '\nintegerFactors(n)\n\n' + alignedTable(lstTest
+        .map(integerFactors)
+        .map(
+            (x, i) => [lstTest[i], '-->'].concat(x)
+        ), 2, alignRight
+    ) + '\n';
+
+})([25, 45, 53, 64, 100, 102, 120, 12345, 32766, 32767]);